Food Experiments in the Unit Operations Lab. Mohammad Biswas, Laura Kelley, William Josephson & David Mills Chemical Engineering Dept. Auburn University 2007 AIChE Annual Meeting Salt Lake City, Utah. The Lab. CHEN 3820 – Chemical Engineering Laboratory I Jr Level Course
Mohammad Biswas, Laura Kelley,
William Josephson & David Mills
Chemical Engineering Dept.
2007 AIChE Annual Meeting
Salt Lake City, Utah
CHEN 3820 – Chemical Engineering Laboratory I
“Design an experiment that teaches something about food”
My motivation – lack of knowledge, desire for variety, importance of the topic
My expectations – chemistry heavy approach
Investigate relationship between boiling time & spaghetti stickiness
o Generally, you are to determine the relationship between
boiling time and stickiness of spaghetti noodles.
o You should also consult other sources while investigating why spaghetti will stick to a ceiling or wall when it is “done.”
• Operation – Normal
o Remove a few spaghetti noodles from boiling water at regular time intervals
o be sure to use caution when removing the spaghetti noodles from boiling water
o Throw noodles at a nearby wall to check for ‘al dente’
o Record visual observations on firmness, color, and stickiness
• Students should be able to utilize resources from outside of the classroom such as the internet to explore what is changing in the noodles with respect to cooking time. Students should understand that it is the starch in the noodles that gives the stickiness to them. As the noodles cook longer the starch is leached from the noodles into the surrounding water. Some of the starch breaks down into the sugar dextrin, coats the noodles and makes them sticky when removed from the water. Maltose and glucose are also products of the starch degradation and contribute to the pasta’s stickiness.
• Students should examine what would happen if the noodles were cooked in a very large amount of water, or a very small amount of water? The starch concentration would vary as would the stickiness of the noodles.
• Students should understand and state that as the length of
cooking time is increasing the concentration of starch in the
surrounding water is increasing. This means that as cooking time increases the spaghetti noodles should be growing stickier and stick better to a wall.
• It should also be understood that as cooking time increases
more water is impregnating the noodles themselves, moving
closer toward being fully saturated. This causes the noodle to
lose rigidity and become more pliable.
The Fat-O-Meter (aka “Hot Fat”)
Q = m CPΔT
Use the Easy Bake to determine fat content?
Procedure – standard sample size, standard heating time, monitor ΔT
Generate Drying Curves
Vary initial water content, shape
Monitor water content via weighing
No food experiment
Butter Experiment has been part of CHEN 3820
Base Case is w/ KitchenAid mixer & whipping cream
Fat in milk exist as droplets covered in a membrane. The churning process breaks this membrane exposing the fat globules. Additional churning results in the globules coalescing into a separate fat phase3.
All fats, including milk fat, are triesters of glycerol. These molecules contain three carboxyl groups and have three long organic tails as can be seen in the saturated fat molecule seen in Fig.2.
Figure 2: Saturated fat molecule
As was previously stated, adding salt to milk or whipped cream can reduce churning time. This phenomenon could be the result of the electrostatic interactions between the long organic chains of the fat and the ions introduced into the milk emulsion.
Butter – will continue, will tweak (e.g., yield)
May repeat student designed experiment
To the students
CHEN 3820 Chemical Engineering Laboratory I